The LH4 was designed by a company called Lightning hybrids and as stated
above, is powered by a Biodiesel engine. Only 3 cylinders are needed to get
the vehicle moving and power the hydraulic pump that takes the place of a
traditional electric motor. Combined, the system is good for 100mpg, which
will do very well in the race for the Automotive X Prize.

The Biodiesel-Hydraulic combination is also a wonderful choice in terms of
performance. When the need arises, the LH4 can launch to 60mph in just under
6 seconds, which is nothing to sneeze at given the high fuel economy number
it is able to return. The looks of the LH4 aren’t bad either.

The Good News

When I first read about hybrid automobiles 20 years or so ago, two models were
on the table: electric and hydraulic. With the advent of the Prius a few years
back, and the rush of other car companies to follow suit, the term "hybrid"
has become almost synonymous with "electric hybrid." There were a
few announcements early on that some automakers were looking at the hydraulic
approach, but announcements have been few and far between and production vehicles
available to the consumer or commercial markets have been non-existent.

Please correct me if I’m wrong on this; if anyone is selling hydraulic hybrids
I’d like to hear about it. Plus I’d be very interested to know how they’re doing…

I always liked the elegance of the hydraulic model for hybrid automobiles:
capture the forward momentum you normally lose every time you brake in the form
of hydraulic compression. Then turn around and unleash that pressure next time
you want to acelerate. This approach may provide a better fuel savings than
electric hybrids can — it certainly will for larger vehicles whose greater
mass will pump massive amounts of force into the hydraulics system. You’ve got
to love that 0 to 60 in six seconds. That’s some pretty nice acceleration for
a car that gets 100 MPG. Plus, the expectation is that hydraulics systems are
more economical than the battery systems used in electric hybrids — giving
the hybrid shopper less sticker shock.

Perhaps most imortantly, having two working models for how to deploy a hybrid
vehicle means competition. Hydraulic hybrids will drive improvements to electric
hybrid systems and vice-versa. And one day, these two models might meet to provide
the ultimate hybrid. Get that fossil-fuel-burning engine out of the loop and
provide your primary power with an electric engine. Then use hydraulic brakes
to capture your lost forward momentum. Now that would be an efficient model.

I think I remember UPS is testing a hydraulic hybrid for their delivery trucks.

Ron

The hydraulic hybrid UPS truck is scheduled to be introduced “between 2009 and 2010″ according to the article here.

Dennis

UPS is now testing a small fleet of hydraulic hybrid trucks. With all the stop and go they do it is a good fit.
They estimate a 50% decrease in fuel consumption. I guess we will see.
If this works out we will probably be seing systems like this on Garbage trucks; busses and delivery vehicles.